Pipe joint gaskets including anti-slip segments for preventing the separation of interconnected, telescoping metal pipes in applications where a fluid such as water for fire mains is held under high pressure are known in the art. Exemplary gaskets are described in U.S. Pat. Nos. 5,295,697 and 5,464,228 in which a rubber gasket, serving as a fluid seal, includes toothed metal segments spaced around its inner perimeter. The toothed metal segments bite into the outer surface of the spigot of the inserted pipe and prevent withdrawal of the inserted pipe from a bell end of the other pipe. A shortcoming of such gaskets is that during fluid pressurization of the interconnected pipes, excessive axial thrust force generated by the resulting hydrostatic pressure can cause the metal segments to exert destructive radial loads upon the inner axial surface of the bell end and the outer axial surface of the spigot end. In many instances, these radial loads are great enough to fracture the spigot and bell ends of the metal pipes.
Since anti-slip segments are known to destructively impinge upon metal pipes, the use of gaskets containing such or similar segments for preventing the separation of interconnected plastic pipes has been limited, especially in high pressure applications. Instead, plastic pipes, such as those formed from thermoplastic materials including polyethylene, polybutylene, polypropylene and poly(vinyl chloride) or PVC, are joined together by means of a bell-and-spigot gasket-sealed joint utilizing gaskets referred to as Reiber gaskets.
A Reiber gasket consists of a continuous steel band either externally or internally bonded to an elastomer annular body. The Reiber gasket is locked into place within an annular groove of the bell and functions to prevent the gasket from becoming dislodged therefrom. The Reiber gasket fails however to sufficiently restrain axial separation of plastic pipes along a joint upon fluid pressurization of the pipe at high pressure. Accordingly, there is a need for a gasket that is capable of forming a seal between plastic pipes, while preventing separation of the pipes at high pressure.